A vacuum insulation material is a type of high-functional insulation material utilizing the low thermal conductivity of a vacuum by decompressing an inner space into the vacuum state. The vacuum insulation material is typically produced in a form of panel with a predetermined thickness.
The vacuum insulation panel may include an envelope material defining a predetermined inner space, and a core material accommodated within the envelope material to support the envelope material such that the envelope material can maintain the predetermined space.
The envelope material is to maintain a vacuum level (vacuum degree, vacuum rate) inside the vacuum insulation material at a constant level and may be made of a multilayered polymer, an aluminum-laminated film or the like.
The core material is made of a so-called glass fiber, silica or the like. Among others, the glass fiber is widely used by virtue of its excellent initial performance and low material cost. However, it has disadvantages in view of requirements of many equipment and much time for preprocessing and poor durability. The silica exhibits long-term reliability but high material cost.
Meanwhile, the inside the envelope material may be shown having a getter for adsorption of gas present in the inner space of the envelope material. The getter is a type of gas absorbent or moisture absorbent for absorbing gas or moisture which is left in the envelope material or newly introduced therein.
The vacuum insulation material generally has a form of flat panel. Thus, when employed in a refrigerator, many sheets of vacuum insulation panels are attached inside walls of a main body of the refrigerator by considering the shape of the main body of the refrigerator. That is, similar to attaching tiles on outer walls of a building, rectangular vacuum insulation panels are attached inside the main body of the refrigerator.